Rotary pump



March 17, 1925.

o. SIEMEN ET AL ROTARY PUMP Filed oct. e, 192,5

Patented lidar. i7, 1925..

unirse OTTO SIEMEN AND JOHANNES HINSCH, OF ST. MARGARETHEN-HLSTEIN, GERMANY.

RDTARY PUMP.

Application led October 6, 1923, Serial No. 667,068.

To all 'whom t may concern:

Be it known that we, O'r'ro SIEMEN and 'JOHANNES HINsoH, citizens of the German which a single rotor is adapted to work inl more than one stage, the pump casing being provided with passages whereby part of the impelled liquid is returned to .the rotor for thereception of a fresh impulse.

The object of the invention is to arrange the di'erent passages so that air or gases drawn' in by the pump together with the liquid can be readily disposed of without aecting the regular function of the pump and so that the pump can be started with a completely open pressure side.

This object is achieved according to the invention by arranging about the rotor space, a spiral, circumferential delivery passage whence a by-pass, of smaller sectional area than the delivery passage, leads back to the rotor space and thence back to the delivery passage, the ports through which the by-pass communicates with the rotor space being arranged on a higher level than the inlet port o f the pum so that air entering the rotor pockets wi be induced to re' main at the base ofthe latter until it arrives at the by-pass expelled by the liquld forced through the latter.

Fig. 1 of the accompanying drawings represents a transverse section of one form of the pump, v

Fi 2, an axial section of the same, taken on t eline II-II of Fig. ll, and

Fig. 3, a vertical axial' section of a pump of modied construction. v

The rotor c is fitted into al casing having a suction side a and a pressure side g. The inlet port b is arranged close to the center and extends principall underneath the rotor shaft so that air rawn in together' with the liquid will remain at the bottom of the pocketsand travel round with the rotor. Arranged circumferentially of the rotor space is a spiral delivery passaged which is branched oif' at e into a diuser passage fi which is of smaller sectional aiea than the main delivery passage and which Iopens. inte the rctorspace through a port orts where it will be `with t b1 arranged above the horizontal center line of the rotor space. Another diifuser pas-` sage f2 which communicates with the rotor space through a port (Z1, opens into the delivery passage at f, close to the junction between the latter and the pressure pipe. The port d1 is arranged between the port b1 and the center of the rotor space.

Part of the liquid driven through the pas-I sage a3 will be diverted at e and returned at high velocity through the passage f1 to the rotor s ace. Here the liquid, which possesses su cient kinetic ener to overcome the centrifugal e'ect o the rotor, passes inwards to the port d1 through which 1t enters the passage f2 whereby it is led back to the delivery passage. As the liquid flows from thc port b1 to the port d1, any air. which, as reviously described, is carried along witli) the rotor from the inlet will be compressed by the liquid and forced into the delivery passage through vthe diffuser 2.

In t e form shown in Figs. l and 2, the ports are situated at the side of the rotor so as to deliver and receive the liquid axially of the latter. The ump will function in the same manner if` uilt as shown in Fig. 3. In this construction the rotor space is annular, tlierotor being formed with blades which overhang the center portion z' of the casing. The ports b and d1 are situated in the portion z' so that the liquid can pass the rotor blades from end 1to end. In the first stage of this ump, the liquid passes from the center to tlie circumference while inthe second stage it passes inwards on the circumference.

In either of these constructions, the pump allows of being started with open ressure side, and the pump 4is therefore particularl suitable for remote control or for automatic operation.

We claim: 1. In a rotary pump of the character described, a casing having a rotorV ace with inlet port, a spiral, circumferentia delivery passa e, and a by-pass of smaller sectional area t an the main delivery passage leadin from the latter back to the rotor space an thence back to the delivery passage, the ports throu li which the by-pass communicates rotor space being on a higher level than said inlet port, substantially as and for the purpose set forth.

2. In a rotary pump of the character de scribed, a casing having a rotor space, a spiral delivery passage arranged circumferentially yrelative to the rotor space, an inlet passage opening into the rotor space near and princi allyunder the center thereof, and two diiiuser passages of smaller sectional area than the delivery passage communicating with said rotor space through ports arranged above the horizontal center line and at different distances from the center, the iiifuserpassages vbeing also in communication With the delivery passage so as to divert liquid from4 the latter into the rotor space through the outermost port and return such diverted liquid to the passage through the innermost port.

3. In a rotary pump of the character described, a casing having an annular rotor space, a spiral delivery passage arranged olrcumferentially relative to said rotor space, an inlet passage opening into said rotor space radially outside and principally under the center thereof, and two diffuser passages of smaller` sectional area than the.

delivery passage opening radially into said rotor space from opposite directions and above the horizontal center line of the rotor4 OTTO SIEMEN. JOHANNES HINSCH. 

